Nasa's Mars rover has made its "most unexpected" discovery since it landed on the red planet in 2012: rocks made of sulphur. On 30 May, the Curiosity rover "happened to drive over a rock and crack ...

The sulfuric lake of Kawah Ijen Mountain's cauldron, Indonesia Wikimedia Commons Even a Dante or a Milton would be struck dumb: inside the crater of the Kawah Ijen volcano lies a landscape bereft ...